Project Summary/Abstract ? Project 1 One in four women has moderate to severe symptoms of some type of pelvic floor disorder and up to 1 in 7 undergo surgery for these conditions in her lifetime. Associations between vaginal parity, pelvic organ prolapse and pelvic floor symptoms are well established; for many women, the stage for future pelvic floor disorders is set with the first vaginal delivery, yet we know little about how to maximize recovery following this seminal event. This knowledge gap limits developing strategies to modify risks in order to prevent deterioration of pelvic floor support and symptoms after vaginal delivery. Further research that provides insight into the earliest onset of the pathogenic process is needed. Intra-abdominal pressure (IAP), the focus of Project 1, is a direct measure of the forces experienced by the pelvic floor but has rarely been studied except in limited clinical settings. Our group has developed and tested a novel intra-vaginal transducer that measures IAP and wirelessly transmits the data to a small, pager-like data storage device. In this project, we plan to use this system to study how IAP impacts two primary outcomes at 1 year postpartum: 1) pelvic floor support and 2) pelvic floor symptoms. The scope of this project is relevant to NICHD's described mission, to ensure that ?women suffer no harmful effects from reproductive processes?, and specifically addresses pelvic floor disorders, as emphasized in the portfolio of the Gynecologic Health and Disease Branch. This project will use the Primiparous Cohort established by the Clinical Coordination Core to achieve these aims: Aim 1: Determine whether IAP measured at 8 weeks postpartum during a) lifting and b) abdominal muscle endurance testing predicts pelvic floor support and symptoms 1 year postpartum. Aim 2: Determine whether IAP measured for one week during daily life at 6 months postpartum predicts pelvic floor support and symptoms 1 year postpartum. Exploratory Aim 3: Determine whether measures of muscular fitness modify the effect of IAP during lifting on pelvic floor support at 1 year postpartum. Translational aim: Using data from Aim 2 of this Project and Project 2, in which physical activity is measured using accelerometry for a 7 day period at 6 months postpartum, explore the relationships between data obtained from the vaginal pressure sensor and wrist-worn accelerometry.